Making it isn't difficult. You only need tea and time. (A bit of citrus and sugar wouldn't hurt either, but they're not essential.) Here's how I like to make cold-brew iced tea:
1. Place 5 tablespoons loose tea or 10 teabags in a glass or plastic 4- to 8-cup container
I usually do a mix of half black tea and half herbal tea, but you can mix and match any way you please. The herbal tea could be fruity or it could be nutty, or you could throw some green tea into the mix instead of—or in addition to—the black tea. When choosing flavored or fruit-infused teas, just think about what flavors you think taste great together in a pie or a punch: how about a few scoops of mango tea, a few of cherry, and a few of black? Or a combo of peach, raspberry, and green tea? Mint tea is always a great addition, too. Really, anything goes—if you like it, it will probably be delicious. Martha is right about one thing though: avoid anything smoky or too overpowering.
2. Cover the teabags with (at least) 4 cups cold—preferably filtered—water
As with cold-brew coffee, cold-brew tea is all about making an infused concentrate and then diluting it just before drinking it. So I use 4 cups of water so that the chilling mix will take up less space in my refrigerator. If you would rather cut out the middle man and steep the tea in your serving pitcher (in which case you'll need 8 cups of water), feel free.
3. Cover the container and chill for at least 4 hours (or up to 48)
I like to let it go between 8 and 12 hours, but if you leave it for as much as 48 hours it will still be fine. That's the brilliance of cold brew—even when steeped over a long period of time, the tea will stay smooth and refreshing until you have time to tend to it.
4. While the tea is chilling, make simple syrup
If you're going the sweet tea route (which is highly recommended), you'll want some sweetener. Since the tea won't be hot, you won't be able to dissolve sugar directly into it. Instead, make a simple syrup of equal parts sugar and water to add to the tea once you're ready to serve. You'll need about 1/3–1/2 cup simple syrup to sweeten 8 cups of tea.
5. Strain the tea or remove the tea bags
If you've used tea bags, don't forget to squeeze the liquid from those tea bags back into the cold-brewed tea. If you've used loose tea instead of teabags, you'll want to use a fine-mesh sieve, specialty tea strainer, a colander lined with cheesecloth, or a funnel or Chemex with a coffee filter.
If you've made a concentrate, you can either pour it into a serving pitcher along with 4 cups more cold water, or you can leave as is, diluting as you go if you plan to drink it all yourself—with seltzer or even lemonade if you're feeling fiesty.
6. Dilute and sweeten with simple syrup
Remember, the cold-brew tea itself will be sweeter than if you'd done it using a hot-brew method, so add less sweetener than you'll think you need. Feel free to sweeten all at once, or put the syrup in a large creamer pitcher to let tea drinkers sweeten as they please. This is also a good time to squeeze in the juice of a lemon or an orange, or whatever citrus you think would taste best with your chosen herbal teas. If you have it, a sprig of fresh mint is a nice touch, too.
One word of warning though. You'll probably want to get another batch going as soon as you set that one out. Because—if this Southern boy's empty pitcher is any indication—that sweet tea will surely be gone in less than one afternoon.
